The present invention relates to the field of valves and valve controllers. Pinch valves are well known to those of ordinary skill in the art. Typically, pinch valves employ a spring-loaded system. Prior art pinch valves have certain disadvantages. Over time, these pinch valves often cut into the tubing that they cooperate with. These pinch valves require power to maintain a valve held open or pinched off. The earlier designs required significant actuation power and high profiles.
Accordingly, there is a need for an improved pinch valve that addresses and overcomes the disadvantages of the earlier pinch valves. In addition, it is desirable that the pinch valve provides a positive pinch-off without cutting into the tubing it cooperates with. It is also desirable the pinch valve provides an adjustable pinch-off aperture. It is further desirable that the pinch valve provides a high force pinch-off while requiring low activation power, preferably about 5 watts maximum at about 5 volts, while requiring no power to hold in the valve. Furthermore, the need exists for a pinch valve that has a profile of less than about 0.700xe2x80x3 high, is magnetically and thermally isolated from the tubing, and allowing for non-threaded tubing to be installed and removed.
The present invention is for a pinch valve for pinching off a tube, the valve comprising a linear actuator, a moveable back piece against which pressure can be applied, and a pointer rotatably connected to the linear actuator wherein the pointer is not in contact with the tube when the pinch valve is in the open position, but is essentially perpendicular with the tube in the pinched-off position.
It is also contemplated that the linear actuator may further comprise a follower. Furthermore, the linear actuator may also comprise a motor. In addition, a guide may be included for guiding the pointer. Preferably the linear actuator is essentially parallel to the tube and the pointer is perpendicular to the tube when the valve is in the closed or pinched-off position.
In the preferred embodiment it is contemplated that the moveable back piece is an eccentric. Preferably, the eccentric is adjustable and is selectively moved between a minimum and maximum position which controls the amount of pinch off.
A biasing spring may be provided for holding the tubing in place. It is also contemplated that more than one biasing spring may be utilized for improved stability.
The aspects, features and advantages of the present invention are readily apparent from the following description of the preferred embodiments when taken in connection with the accompanying drawings.